In the current specifications of the third generation mobile networks (referred to as UMTS), the system utilises the same well-known architecture that has been used by all main second-generation systems. A block diagram of the system architecture of the current UMTS network is presented in FIG. 1. The UMTS network architecture includes the core network (CN), the UMTS terrestrial radio access network (UTRAN), and the user equipment (UE). The core network is further connected to the external networks, i.e. Internet, PLMN, PSTN and/or ISDN.
The GSM Phase 1/2 Core Network consists of network switching subsystem (NSS). The NSS further consists of the following functional units: Mobile Switching Center (MSC), Visitor Location Register (VLR), Home Location Register (HLR), Authentication Center (AC) and equipment identity register (EIR). The GSM Phase 2+ enhancements to the GSM phase 1/2 CN are serving GPRS (General Packet Radio Service) support node (SGSN), gateway GPRS support node (GGSN) and CAMEL service environment. The most important new feature that is introduced with GPRS is packet switching (PS). For UMTS, only minor modifications to the GSM Phase 2+ core network are needed. For instance, allocation of the transcoder (TC) function for speech compression.
UTRAN architecture consists of several radio network subsystems (RNS). The RNS is further divided into the radio network controller (RNC) and several base stations (BTS, referred to as B nodes in the 3GPP specifications).
In this architecture there are several different connections between the network elements. The Iu interface connects CN to UTRAN. The Iur interface enables the exchange of signalling information between two RNCs. Iur(-g) is in principle same as Iur but it is formed between two different type of radio access network, i.e. GERAN/UTRAN and therefore between two different types of network element, i.e. between base station subsystem (BSS) and RNC, respectively, for multiradio purposes. In the following text we refer to these two interfaces using notation Iur. The signaling protocol across the Iur interface is called radio network subsystem application part (RNSAP). RNSAP is terminated at both ends of the Iur interface by an RNC. Also there are Gb and A interfaces for connecting base station controller BSC and core network CN in GERAN. They can also be used to exchange load information (common measurements) between Iu mode RNCs/BSCs and A/Gb mode BSCs. Operator specific load measures could apply to those interfaces as well.
The Iub interface connects an RNC and a node B. The Iub interface allows the RNC and node B to negotiate about radio resources, for example, to add and delete cells controlled by node B to support communication of dedicated connection between UE and Serving RNC (S-RNC) information used to control the broadcast and paging channels, and information to be transported on the broadcast and paging channels. One node B can serve one or multiple cells. UE is connected to node B through the Uu radio interface. UE further consists of a subscriber identity module (USIM) and mobile equipment (ME). They are connected by the Cu interface. Connections to external networks are made through Gateway MSC (towards circuit switched networks) or GGSN (towards packet switched networks).
Radio Resource Management (RRM) e.g. in the GERAN (GSM/EDGE Radio Access Network; GSM, Global System for Mobile Communications; EDGE, Enhanced Data rates for GSM Evolution) and the UTRAN is responsible for utilization of air interface resources. The RRM is needed for e.g. maintaining the QoS (Quality of Service), planned coverage, and for offering high capacity. The RRM enables optimising service capacity and capability. The full scope of the RRM is large, and it can be divided into handover, power control, admission control, load control and packet scheduling functionalities
Also, in coming multisystem, multilayer, or multioperator networks it is essential to utilise all the systems or layers in the most efficient way. For this reason, a new network function, the Common Radio Resource Management (CRRM), is being developed. The main functionality of the CRRM is to be able to direct the connections in the call set-ups and handovers to the optimum cell within optimum radio access technology (RAT) depending on the Quality of Service (QoS) requirements of the connection. The algorithms of the CRRM for the target cell selection and auto-tuning are based on the input parameters read from the respective interfaces, e.g. from the Iur(-g) interfaces. These parameters represent the status information of the different cells. Parameters can be, for example, the total load, RTLoad (RT, Real Time), and NRT Load (NRT, Non Real-Time). Another example in which common measurements have to be reported is the Iur-interface between different Radio Network Controllers (RNC). However, if CRRM is not supported in shared networks, they will loose some competitiveness because CRRM capacity gains cannot be utilized to full extent.
In this application we are considering mobile communication networks shared by two or more operators. Sharing a wireless network can be carried out by at least two different ways. Each operator sharing the network owns or is entitled to use its own air interface carrier or operators share the same air interface carrier, e.g. in national roaming or in mobile virtual network operators (MVNO). A mobile virtual network operator is a notation used for operators that accesses the radio resources via another operator's network. Sharing can also mean a combination of the two above-mentioned solutions.
To allow sharing in a controlled and pre-defined way—according to sharing agreements—operator specific Radio Resource Management (RRM) is needed. This would enable fair sharing of available capacity as well as service differentiation between the sharing operators.
Moreover, network sharing in the long term will be difficult if there is not enough individual control of the radio resources. In order to build longstanding and fruitful co-operation relationships and sharing agreements between the operators, more control over the resources is needed. This requires that each operator have to be able to control the resources dedicated to it, but also the reporting of the usage of the resources is needed.
Furthermore, because the capacity has not been so important in the rollout phase of shared networks, the sharing problem has been solved with over-dimensioning and mutual trust. However, there is no way to monitor the resource usage in specific cells for each operator, which makes it difficult to divide investments costs between the operators. The purpose of this invention is to provide means for exchanging usage information in the multioperator mobile networks. Despite the high amount of different reporting alternatives of the present invention, they are not contradicting each other, but are only options for different needs. Also the purpose of the present invention is to provide a fair and easy solution to monitor the usage of the shared network.